Tensile Behaviour of Functionally Graded Braided Carbon Fibre/Epoxy Composite Material

The primary objective of this research work was to investigate experimentally the tensile behaviour of Functionally Graded Materials (FGM) made from tubular braided composites and to find out the relationship between the tensile property of the FGM and that of the corresponding non-FGM. Composites were made using tubular braided carbon fibre fabrics and an epoxy resin. The FGM specimens had varying braiding angles and the non-FGM specimens had constant braiding angles. The effect of braiding angle on the composite properties was established from the test results for the non-FGM specimens. It was shown that both the tensile strength and modulus decreased as the braiding angle increased. The tensile behaviour of the FGM specimens was demonstrated to be related to that of the non-FGM specimens. The tensile modulus of an FGM specimen could be estimated from the tensile moduli of a series of non-FGM specimens. The tensile strength of an FGM specimen was a function of its largest braiding angle, and was higher than that of a non-FGM specimen with a braiding angle equal to this largest braiding angle.